What are Storage Controllers?

Storage Controllers?

Consider the storage controller card as an embedded processor chip that is able to perform a variety of tasks. It manages the transfer of data between the device that stores the data and SATA controller card.

In essence, it’s an independent “space” that controls the volume exchange, and provides an interface to SSDs, HDDs and other media external to it and caches active data to facilitate the flow of data.

Functions of Storage Controllers

Every storage controller has an output and input path for communication between the storage network and Direct Attached Storage (DAS).

A processor is installed which handles the I/O functions, controlling the Redundant Array of Cost-Effective Disks (RAID) as well as the volume that is being transmitted through the controller.

It also handles the complicated tasks of making snapshots, cloning and thin provisioning, and reduplication for safe and secure access to data throughout the data center’s lifecycle.

Types of Storage Controllers

Storage controllers can be classified into:

  • SATA Host Bus Adapters
  • Fiber Channel Host Bust Adapters
  • RAID Controller Cards
  • SAS Expander ICs
SATA controller card.

Factors that impact the performance of Storage Controllers

Storage Controllers are among the major facilitators in the performance of data centers. In essence, it can be said that the total flow of data is influenced by the performance of a storage controller.


The most important aspect that influences the data center’s environment is the speed. Thus, the most important thing should be a speedy storage infrastructure that can process data and carry out functions that involve colocation of data.

Communication is another crucial aspect. The controller should be able to effectively communicate with the disk drives that are attached to ensure a smooth data transfer. The drives have to be connected to one another since the controller’s performance will directly correlate with number of drives that are attached.

Data Bus Capacity:

In the past the Solid State Drives were able to exceed their storage controllers’ speeds,, causing delays between servers and storage units. This meant that they needed to be reduced in size for the same speeds.

However, now that storage controllers have larger capacities (up up to 12Gbps) They can now handle the data flow of several storage units at once which makes the issue of latency irrelevant.

Thin Provisioning & Snapshots:

Insufficient provisioning, creating of clones and snapshots of system images made every second could take up storage space particularly during the peak processing times. Storage controllers must reserve space on the storage devices to accommodate this However, if additional data must be stored, the allocated space must be released of the system image which can slow down the overall performance.

Automated Tiering:

Another element that impacts how well Storage Controllers is the automated tiering. It’s a process whereby data that is not used often is stored on slow speed drives, like that of the hard drive. It is later shuffled as the data fetching process for that particular part is more active.

When tiering is automated, controllers are required to study patterns of access and the statistics of different applications to transfer data. This can affect the performance quality.

Pros and Cons of Different Types of Storage Controllers:

Every Storage Controller comes with an internal processor that regulates information flow, regulates speed, and performs other functions. These are the fundamentals that we’re discussing. In addition, the majority of storage controllers are created by their makers or specifically designed for a specific purpose or task. They are also only accessible to a select group of servers in accordance with company agreements, or open to everyone (white boxes).

Each storage controller has pros and cons. Some are more efficient while others are more reliable. Some have even increased performance in terms of heat resistance. The vendors will only inform you about the advantages to their control systems for storage. However, it’s up to you as a buyer to weigh the negatives and select the one which best suits your requirements.

In this article, we’ve explained the main characteristics of each kind of storage controller you must think about in deciding which controller to purchase:

Custom Designed:

Certain Storage controllers come with specific hardware specifically designed for these controllers. For instance, Custom ASICs (Application Specific integrated Circuits) or FPGAs (Field Programmable Gate Arrays) are common in custom controllers. These storage controllers could also comprise custom logic, processors , and even custom software to support their functions.


The reliability and performance are the main benefits that custom designed controllers offer. Performance is achieved through custom-designed hardware for data colocation and encryption, as well as compression and high-performance operation. Reliability is derived from built-in error detection and reduces the amount of components.


The disadvantages of custom-designed storage controllers are their price and the time they take to construct. It typically takes longer to design a custom storage controller due to the extra components that they need.


Purpose-built storage controllers are able to have an understanding of specific hardware part of the system. Hardware that is common to all systems is included in the package.


This can be accomplished by:

  • Disruptive and non-disruptive service
  • The system can be scaled by adding adapters


The most significant drawback of custom-built storage controllers becomes evident as newer hardware models are released. New processors require new motherboards , and they might or might not work with the integrated controllers for storage. It will require a significant investment to purchase the new system.

Commodity Server-Based:

Commodity storage controllers that are server-based are able to run on a server via drivers. The server may be brand or white boxed, it does not really matter.


The benefit of using a standard server-based storage device over others is the cost. Implementation of the servers are straightforward and the connectivity can be achieved without a significant cost.


Commodity storage controllers that are server-based cannot easily be scaled. In addition, the upgrading, replacement of hardware components, and acquiring support is a major issue.

Best Brands for Buying Storage Controllers

The best Storage Controllers are offered from HP, IBM, Dell, Avago, Adaptec, LSI and other brands similar to. The best storage controllers are produced through Adaptec & LSI.

These controllers comprise SAS/SATA Host Bus adapters, Fibre Channel Cards, SAS Expander Cards SAS/SATA RAID Controller Cards and similar adapters which allow connectivity between storage mediums and servers.

When Do You Need A Storage Controller?

Storage controllers serve multiple purposes. If your company has one of the following requirements it is possible benefit from a quality storage controller.

If the server requires:

  • Multiple storages, like HDDs SSDs, HDDs and External Storage
  • More ports to connect hard drives
  • Data transfer at high speed between the computer and drives
  • Better volume management
  • Pre-caching of data that is active

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